
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>获取短信验证码倒计时</title>
<!-- 第二步：写好css样式部分 -->
<style type="text/css">
form{
    margin:200px auto;
    width:500px;
}
label{
    font-size:14px;
    color:#555;
    line-height:40px;
    margin-right:10px;
}
input{
    width:212px;
    height:38px;
    border-style:none;
    padding:0 4px;
    border:1px solid #C8C8C8;
    margin-right:10px;
    outline:none;
}
.msgs{
    display:inline-block;
    width:104px;
    color:#fff;
    font-size:12px;
    border:1px solid #0697DA;
    text-align:center;
    height:30px;
    line-height:30px;
    background:#0697DA;
    cursor:pointer;
}
form .msgs1{
    background:#E6E6E6;
    color:#818080;
    border:1px solid #CCCCCC;
}
</style>

</head>
<body>
    <!-- 第一步：写好获取验证码的布局 -->
<form>
	<label style="float:left;">验&nbsp;&nbsp;证&nbsp;码</label>
	<input type="text" class="c_code_msg" style="margin-right: 10px;">
	<span class="msgs">获取短信验证码</span>
</form>
<script type="text/javascript" src="./js/jquery-1.8.3.min.js"></script>
<script type="text/javascript">
$(function  () {
	//第三步：获取短信验证码，按钮进入倒计时
	var validCode=true;
	$(".msgs").click (function  () {
		var time=30;
		var code=$(this);
		if (validCode) {
			validCode=false;
			code.addClass("msgs1");
		var t=setInterval(function  () {
			time--;
			code.html(time+"秒");
			if (time==0) {
				clearInterval(t);
			code.html("重新获取");
				validCode=true;
			code.removeClass("msgs1");

			}
		},1000)
		}
	})
})
</script>
</body>
</html>